Outcomes of Antibiotic-Impregnated Calcium Sulfate, Reamer-Irrigator-Aspirator, and Locked Intramedullary Static Spacer in the Treatment of Periprosthetic Joint Infection in the Multiply Revised and Infected Knee: A Single-Center Case Series

Background

Periprosthetic joint infection after total knee arthroplasty is commonly treated via 2-stage revision utilizing either articulating or static antibiotic cement spacers. While recent literature exhibits a slight functional advantage in favor of articulating spacers, those patients with a history of recurrent infection/multiple revision procedures are frequently excluded from these studies. The purpose of this study was to report infection eradication rates and efficacy of utilizing antibiotic-loaded locked intramedullary nail for infection for the multiply revised, infected total knee arthroplasty.

Methods

A retrospective review was performed of all consecutive patients receiving static spacers between 2017 and 2020 at an academic medical center. Surgical techniques for all patients included irrigation and debridement using a reamer-irrigator-aspirator, injection of antibiotic-loaded calcium sulfate into the intramedullary canal, and nail placement. Antibiotic-loaded cement is then used to create a spacer block in the joint space. A Cox proportional hazard regression was run to identify risk factors for reinfection.

Results

Forty-two knees in 39 patients were identified meeting inclusion criteria. Overall, there was an 68.8% infection eradication rate at an average of 46.9 months following spacer placement. The only risk factors identified on cox regression were increasing number of previous spacers, a surrogate for previous infections (hazards ratio = 14.818, P value = .021), and increasing operative time during spacer placement (hazards ratio = 1.014, P value = .039).

Conclusions

Use of static spacers, in conjunction with reamer-irrigator-aspirator and antibiotic-loaded calcium sulfate, can be effective in treating chronic, complex periprosthetic joint infections in the setting of bone loss and or soft-tissue compromise and produced similar results to more simple infection scenarios.

Maximizing Adherence and Minimizing Time to Antibiotics: A Multidisciplinary Institutional Trauma Bay Protocol for Single Antibiotic Prophylaxis in Open Fractures

OBJECTIVES

To determine if a multidisciplinary institutional protocol can optimize the time to antibiotic (Abx) administration for open fractures (openFx) and improve compliance with the administration of Abx prophylaxis during trauma activation.

METHODS

DESIGN

Retrospective pre-post study design.

SETTING

Single Level II Trauma Center.

PATIENT SELECTION CRITERIA

All patients who triggered a trauma activation with suspected openFx and were treated according to the institutional single antibiotic regimen were eligible for inclusion. Patients were excluded if fractures did not involve the appendicular skeleton. Patients treated before implementation of a standardized institutional protocol where premixed IV bags of antibiotics were stocked in automated dispensing systems within ED trauma bays (January 2021-October 2022) were defined as the "pre" group and those treated following implementation the "post" group.

OUTCOME MEASURES AND COMPARISONS

The primary outcome was time from trauma bay arrival to antibiotic aministration, measured in minutes, with comparisons made between preprotocol and postprotocol implementation. Secondary outcomes for comparison included rates (%) of time to Abx <60 minutes, allergic reactions, acute kidney injury, ototoxicity, surgical site infection, multi-drug-resistant organisms identified in blood or biopsy cultures in cases requiring reoperation, and Clostridium difficile infection in the gastrointestinal system, confirmed by stool test results, within 30 days.

RESULTS

Twenty-four patients (mean age 39.5 ± 16.3 years) met the criteria after protocol implementation compared with 72 patients (mean age 34.3 ± 14.8 years) before implementation. Implementation of the institutional protocol resulted in a significant reduction in the time to Abx administration for openFx from 87.9 ± 104.6 minutes to 22.2 ± 12.8 minutes in the postprotocol group ( P < 0.001). In addition, only 53% in the preprotocol group received Abx within 60 minutes compared with 96% in postprotocol group ( P < 0.001). Post hoc power analysis revealed that the study was powered at 92% (effect size = 0.72) to detect a significant difference between the preprotocol and postprotocol groups.

CONCLUSION

This study provides evidence that a multidisciplinary institutional protocol for the administration of Abx prophylaxis can be an effective strategy for optimizing the time to Abx administration in cases of suspected openFx. This protocol may be implemented in other trauma centers to optimize time to Abx administration for openFx.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Postoperative wound complications in extensile lateral approach versus sinus tarsi approach for calcaneal fractures: Are we improving? Updated meta-analysis of recent literature

INTRODUCTION

To analyze recent literature comparing clinical outcomes of displaced intra-articular calcaneal fractures (DIACF) treated with open reduction and internal fixation using the extensile lateral approach (ELA) vs the minimally invasive sinus tarsi approach (STA), with a focus on wound complications.

MATERIALS AND METHODS

A comprehensive literature search was conducted utilizing PubMed, EMBASE, and Cochrane Library databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies published between 2013 and 2022, level of evidence (LOE) I-III, head-to-head comparative studies reporting on clinical outcomes after DIACFs treated with ORIF using ELA versus STA, and literature with full-text written in English were included. Data collection included: publication year, study design, number of surgeons, number of participants, demographic data (mean age at time of surgery, percent male, body mass index, medical co-morbidities), preoperative data (mechanism of injury, Sanders classification, time from injury to surgical fixation), intraoperative data, and postoperative clinical and radiographic outcomes (Böhler angle, angle of Gissane, calcaneal height/length/width).

RESULTS

A total of 21 articles (4 randomized control trials, 17 cohort studies) comprising of 2086 patients with calcaneal fractures, treated with either ELA (n = 1129) or STA (n = 957) met inclusion criteria. The risk of postoperative wound-related complications (RR 2.82, 95 % CI: 2.00-3.98, I2=27 %) and the risk of reoperation (RR 1.85, 95 % CI: 0.69-5.00, I2=67 %) was higher in ELA patients comparted to STA patients. However, the increased risk of postoperative wound-related complications with an ELA vs. STA was shown to be trending downward in recent publications. The ELA group also experienced longer time to surgery, extended operative times, and prolonged hospital stays when compared to the STA group. Radiographic measurements at final follow-up, including Böhler angle, angle of Gissane, as well as calcaneal height, length, and width, showed no statistically significant differences between the two groups.

CONCLUSION

Surgical treatment of calcaneal fractures utilizing the ELA continues to have an increased rate of complications and reoperation when compared to the less invasive STA, yet recent trends in the literature show that this rate is decreasing. Operative treatment of calcaneal fractures via either an ELA or STA can both achieve comparable postoperative radiographic outcomes.

LEVEL OF EVIDENCE

Therapeutic Level III.

Early versus Standard Weight Bearing Following Operative Treatment of Tibial Plateau Fractures: Do We Really Have to Wait So Long?

Postoperative management of tibial plateau fractures classically involves a prolonged period between 10 and 12 weeks of nonweight bearing or partial weight bearing. In recent years, there has been some support for earlier weight-bearing protocols although this remains controversial. The goal of this study was to investigate the difference in outcomes between early weight-bearing (EWB) and traditional weight-bearing (TWB) protocols. This investigation is a retrospective review of 92 patients treated with open reduction and internal fixation of tibial plateau fractures at a single institution, from August 2018 to September 2020. Subjects were divided into EWB (< 10 weeks) and traditional nonweight bearing groups (≥ 10 weeks). Key outcome measures collected include injury classification, mechanism of injury, surgical fixation method, bone grafting, time to full weight bearing, radiographic time to union, range-of-motion, all-cause complications, and subsidence at an average follow-up time of 1 year. The EWB group had an earlier average time to weight bearing versus the TWB group (6.5 ± 1.4 vs. 11.8 ± 2.3 weeks, p < 0.0001). There was no difference in the classification of fractures treated between the two groups, with Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association B3 fractures the most common in the EWB group, and C3 fractures the most common in the TWB group. Radiographic time to union was no different between the two groups (93.5 ± 53.7 days for EWB vs. 103.7 ± 77.6 days for TWB, p = 0.49). There was no significant difference in complication rates or subsidence. Following operative treatment of tibial plateau fractures, patients who underwent a weight-bearing protocol earlier than 10 weeks were able to recover faster with similar outcomes and complications compared with patients who started weight bearing after 10 weeks or more. LEVEL OF EVIDENCE:  III.

No Difference in Acute Outcomes for Patients Undergoing Fix and Replace Versus Fixation Alone in the Treatment of Geriatric Acetabular Fractures

OBJECTIVES

To compare acute outcomes between patients undergoing fix and replace (FaR) versus open-reduction and internal fixation (ORIF) alone in the treatment of geriatric acetabular fractures.

METHODS

DESIGN

Retrospective Cohort Study.

SETTING

Single Level 2 Trauma Center.

PATIENT SELECTION CRITERIA

Consecutive acetabular fracture patients ≥ 55 years of age treated by two orthopaedic trauma surgeons at one tertiary care center from January 2017 to April 2022 with FaR versus ORIF were identified. Included were those with complete datasets within the 180-day global period. Excluded were patients with previous ORIF of the acetabulum or femur, or revision total hip arthroplasty.

OUTCOME MEASURES AND COMPARISONS

The primary outcomes were length of hospital stay (LOS), postoperative weight-bearing status, postoperative disposition, time to postoperative mobilization, and 90-day readmission rates. Secondary outcomes compared included demographic information, injury mechanism, surgical time, complications, revisions, and preoperative and postoperative Hip Disability and Osteoarthritis Outcomes Score for Joint Replacement (HOOS Jr.) scores. These were compared between FaR and ORIF groups.

RESULTS

Seventeen FaR patients (average age 74.5 ± 9.0 years) and 11 ORIF patients (average age 69.4 ± 9.6 years) met inclusion criteria. Mean follow-up was 26.4 months (range: 6-75.6 months). More FaR group patients were ordered immediate weight-bearing as tolerated or partial weight-bearing compared with ORIF alone (70% vs. 9.0%, P = 0.03). More patients in the FaR group had pre-existing hip osteoarthritis compared with ORIF alone (71% vs. 27%, P = 0.05). Fracture classification ( P = 0.03) and Charlson Comorbidity Index ( P = 0.02) differed between the 2 groups. There were no other differences in demographics, LOS ( P = 0.99), postoperative disposition ( P = 0.54), time to postoperative mobilization ( P = 0.38), 90-day readmission rates ( P = 0.51), operative time ( P = 0.06), radiographic union ( P = 0.35), time to union ( P = 0.63), pre- ( P = 0.32) or postoperative HOOS Jr. scores ( P = 0.80), delta HOOS Jr. scores ( P = 0.28), or reoperation rates between groups ( P = 0.15).

CONCLUSIONS

FaR and ORIF seem to be sound treatment options in the management of geriatric acetabular fractures. Patients in the FaR group achieved immediate or partial weight-bearing earlier than the ORIF group; however, time to postoperative mobilization did not differ between the two groups. The remainder of acute postoperative outcomes (LOS, postoperative disposition, and 90-day readmission rates) did not differ between the two groups.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Comparison of Outcomes After Reverse Total Shoulder Arthroplasty in Patients With Proximal Humerus Fractures Versus Rotator Cuff Arthropathy

INTRODUCTION

Indications for reverse total shoulder arthroplasty (rTSA) has expanded to encompass complex proximal humerus fractures (PHFs) in recent years. The purpose of this study was to report and assess whether PHF patients treated with rTSA could achieve similar functional outcomes and short-term survivorship to patients who underwent rTSA for rotator cuff arthropathy (RTCA).

METHODS

All consecutive patients with a preoperative diagnosis of PHF or RTCA, 18 years or older, treated with rTSA at a single academic institution between 2018 and 2020 with a minimum 2-year follow-up were retrospectively reviewed. Primary outcomes were survivorship defined as revision surgery or implant failure analyzed using the Kaplan-Meier survival curve, and functional outcomes, which included Quick Disabilities of the Arm, Shoulder, and Hand, and range of motion (ROM) were compared at multiple follow-up time points up to 2 years. Secondary outcomes were patient demographics, comorbidities, surgical data, length of hospital stay, and discharge disposition.

RESULTS

A total of 48 patients were included: 21 patients (44%) were diagnosed with PHF and 27 patients (56%) had RTCA. The Kaplan-Meier survival rate estimates at 3 years were 90.5% in the PHF group and 85.2% in the RTCA group. No differences in revision surgery rates between the two groups (P = 0.68) or survivorship (P = 0.63) were found. ROM was significantly lower at subsequent follow-up time points in multiple planes (P < 0.05). A greater proportion of patients in the PHF group received cement for humeral implant fixation compared with the RTCA group (48% versus 7%, P = 0.002). The mean length of hospital stay was longer in PHF patients compared with RTCA patients (2.9 ± 3.8 days versus 1.6 ± 1.8 days, P = 0.13), and a significantly lower proportion of PHF patients were discharged home (67% versus 96%, P = 0.015).

CONCLUSION

The rTSA implant survivorship at 3 years for both PHF and RTCA patients show comparable results. At the 2-year follow-up, RTCA patients treated with rTSA were found to have better ROM compared with PHF patients.

Reverse Total Shoulder Arthroplasty for Younger Patients: A Comparable Analysis of Patients Older and Younger Than 65 Years

INTRODUCTION

Reverse total shoulder arthroplasty (rTSA) has become a popular option for the surgical management of rotator cuff arthropathy and complex fractures of the proximal humerus. However, there is a paucity of studies evaluating outcomes, especially between patients of different age groups. The purpose of this study was to compare functional outcomes and survivorship between patients older than 65 years (o65) and those 65 years and younger (y65).

METHODS

A retrospective review was conducted at a single academic medical center identifying a consecutive cohort of patients undergoing rTSA between 2018 and 2020. The minimum follow-up time was 2 years. Patients were stratified into two groups for comparative analyses (y65 and o65). Patient demographics, perioperative and postoperative data, and functional outcomes were collected. A Kaplan-Meier survival analysis was conducted to determine survivorship, defined as revision surgery or implant failure.

RESULTS

Forty-eight patients were included for final analysis. Nineteen patients comprised the y65 group while 29 patients comprised the o65 group. No difference was observed in Quick Disabilities of the Arm, Shoulder, and Hand scores at baseline nor at the latest follow-up between the two groups. Patients in the y65 group had significantly greater internal and external rotation (IR/ER) from 3 months to 2 years compared with patients in the o65 group (P ≤ 0.05). Finally, there were no differences in revision surgery rates between the y65 group and the o65 group (11% vs. 14%, P = 1.0). A KM survival analysis revealed no difference in implant failure, necessitating revision surgery between the two groups at the latest follow-up (P = 0.69).

DISCUSSION

Despite a notable difference in the number of baseline comorbidities, there were no notable differences in functional outcomes, survivorship, and revision surgery rates between each cohort. Although both groups had a similar function initially, by 3 months postoperatively, the y65 group had markedly greater range of motion in IR and ER. Longer term survivorship is needed; however, rTSA may offer a reliable option for shoulder reconstruction even in the y65 patient group.

Are complications related to the perineal post on orthopaedic traction tables for surgical fracture fixation more common than we think? A systematic review

BACKGROUND

Traction tables have long been utilized in the management of fractures by orthopaedic surgeons. The purpose of this study was to systematically review the literature to determine the complications inherent to the use of a perineal post when treating femur fractures using a traction table.

METHODS

A systematic review was conducted using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) using PubMed, EMBASE, and Cochrane Library. The search phrase used was "fracture" AND "perineal" AND "post" AND ("femur" OR "femoral" OR "intertrochanteric" OR "subtrochanteric"). Inclusion criteria for this review were: level of evidence (LOE) of I - IV, studies reporting on patients surgically treated for femur fractures, studies reporting on patients treated on a fracture table with a perineal post, and studies that reported the presence or absence of perineal post-related complications. The rate and duration of pudendal nerve palsy were analyzed.

RESULTS

Ten studies (2 prospective and 8 retrospective studies; 2 LOE III and 8 LOE IV) were included consisting of 351 patients of which 293 (83.5%) were femoral shaft fractures and 58 (16.5%) were hip fractures. Complications associated with pudendal nerve palsies were reported in 8 studies and the mean duration of symptoms ranged between 10 and 639 days. Three studies reported a total of 11 patients (3.0%) with perineal soft tissue injury including 8 patients with scrotal necrosis and 3 patients with vulvar necrosis. All patients that developed perineal skin necrosis healed through secondary intention. No permanent complications relating to pudendal neurapraxia or soft tissue injuries were reported at final follow-up timepoints.

CONCLUSION

The use of a perineal post when treating femur fractures on a fracture table poses risks for pudendal neurapraxia and perineal soft tissue injury. Post padding is mandatory and supplemental padding may also be required. Appropriate perineal skin examination prior to use is also important. Occurring at a higher rate than previously thought, appropriate post-operative examination for any genitoperineal soft tissue complications and sensory disturbances should not be ignored.

Distal femur: nail plate combination and the linked construct

Operative fixation of distal femur fractures in patients with osteoporotic bone can be challenging. Treatment with either lateral locking plate or retrograde intramedullary nail alone may not provide adequate fixation to allow for early mobilization. Rather, fixation using the nail plate combination (NPC) to treat distal femur fractures in the elderly may offer improved biomechanical stability to achieve immediate weight-bearing, especially in the setting of complex fracture patterns and osteoporosis. Here, we describe the rationale, step-by-step technique, and outcome following 2 cases: 1 patient treated with a true NPC procedure using retrograde intramedullary nail and standard locking plate, as well as a NPC procedure using a novel locking attaching washer plate.

Scapulothoracic Dissociation: A Review of an Orthopedic Emergency

Scapulothoracic dissociation is a rare and devastating injury that is considered an orthopedic emergency. It is critical to recognize this injury early based on mechanism, physical examination, and radiographic parameters. Initial management should be focused on resuscitation and evaluation for potential limb-threatening ischemia.

Response to Letter to the Editor: Comparing Intramedullary Nailing Versus Locked Plating in the Treatment of Native Distal Femur Fractures: Is One Superior to the Other?

We would like to thank the editors for the opportunity to respond to their letter regarding our study, "Comparing Intramedullary Nailing Versus Locked Plating in the Treatment of Native Distal Femur Fractures: Is One Superior to the Other?" published in the Indian Journal of Orthopaedics. The authors greatly appreciate the insight and thoughtful feedback regarding the findings of our study, which may be skewed by heterogenous data and/or technical aspects of surgical plating and intramedullary nailing. We agree with the editors and believe that higher level randomized trials along with specific studies focused on studying modes and causes for treatment failure are necessary to further elucidate the heterogenous data. Nonetheless, with an overall union rate of about 90% and without significant differences in outcomes, at this juncture, we conclude that either intramedullary nailing or locked plate fixation is acceptable treatment options for distal femur fractures.

Comparing Intramedullary Nailing Versus Locked Plating in the Treatment of Native Distal Femur Fractures: Is One Superior to the Other?

INTRODUCTION

Distal femur fractures make up < 1% of all fractures and 3-6% of all femur fractures. In the literature, both intramedullary nailing (IMN) and locked plating (LP) have shown favorable results, but there is no consensus on a gold standard. The purpose of this systematic review is to compare outcomes of native distal femur fractures treated via IMN versus LP in an effort to determine if one is superior to the other.

METHODS

Systematic review of MEDLINE, EMBASE, and Cochrane Library databases was conducted according to PRISMA guidelines. Only articles published within the last ten years were included. Evidence and study quality were evaluated with the MQOE and Oxford Criteria.

RESULTS

Forty-six articles were included in the review. Fractures treated with IMN were found to have a 93.9% union rate, an average time to union of 19.2 weeks, an average arc of motion of 105.1 degrees, with an average of 14.4 degrees of malalignment. Fractures treated with LP were found to have a 90.2% union rate, an average time to union of 20.5 weeks, an average arc of motion of 104 degrees, with an average of 12.6 degrees of malalignment.

CONCLUSION

Compiled data comparisons revealed no differences in union rate, malalignment, time to union, average arc of motion, or complication rates requiring a return to the operating room. Until higher level randomized data is available, either IMN or LP are acceptable methods of treatment for native distal femur fractures.

Regulation of protamine gene expression in an in vitro homologous system

An in vitro transcription system from the trout testis nuclei was developed to study trout protamine gene expression. The protamine promoter contains, among others, two regulatory elements: 1) a cAMP-responsive element or CRE element (TGACGTCA) which is present in position 5' to TATA box, and 2) GC box (CCGCCC) which is present in position 3' to TATA box. The removal of the CRE-binding protein by titration (by the addition of appropriate oligonucleotides to the incubation mixture) resulted in a decrease in transcription of the protamine gene. These results were confirmed by experiments in which the pure CRE-binding factor (TPBP1) was used, as well as by those where a stimulatory effect of cAMP on protamine promoter transcription was observed. On the other hand, addition of oligonucleotides containing the GC-box sequence enhanced the protamine gene transcription indicating that the protein (Sp1 like) which binds to this sequence acts as a repressor of protamine gene expression. These results confirm the previously proposed model which suggested that the GC box played a role in negative regulation of the protamine gene expression. Involvement of some other factors in this process was also discussed.

The N-terminal quarter of reovirus cell attachment protein sigma 1 possesses intrinsic virion-anchoring function

Previously the receptor recognition domain of the reovirus serotype 3 (T3) cell attachment protein (sigma 1) was mapped to the C-terminal half of the protein using deletion mutagenesis of the reovirus S1 gene. A similar approach has been adopted in the present study to map the domain on T3 sigma 1 that is responsible for incorporation into the virion (i.e., the anchoring domain). Restriction enzymes which divide the T3 S1 cDNA into four segments (5'-I-II-III-IV-3') of similar size were used to generate four mutants, each with a particular segment deleted. The mutants were cloned into SV40 expression vectors and used to transfect COS-1 cells which were subsequently with reovirus serotype 1. Progeny viral particles with truncated T3 sigma 1 proteins incorporated were then identified by radioimmunoprecipitation with a serotype-specific anti-T3 sigma 1 serum. It was found that the mutant lacking I (mutant dl) was totally incapable of being incorporated into the virion, whereas the mutant lacking domain II (mutant dII) was incorporated efficiently. Due to altered antigenicities of the mutants lacking domain III (mutant dIII) or domain IV (mutant dIV), incorporation of these two proteins into virions was less detectable using the above assay. Evidence that domain I (the N-terminal 121 amino acids) alone dictates the incorporation of sigma 1 into the virion came from the subsequent demonstration that a chimeric protein containing domain I fused to chloramphenicol acetyltransferase (CAT) was incorporated into the virion (detectable with an anti-CAT serum) as efficiently as the full-length sigma 1 protein.

The GC box as a silencer

A DNA control sequence GTGGGCGGGGCAAT, or the "GC" box, has been described in the promoter regions upstream of a number of eukaryotic genes transcribed by polymerase II (for review, see Dynan, W.S. and Tjian, R., Nature 316:774, 1985). The "GC" box can occur in single or multiple copies and is the binding site for a protein factor, Sp1, which activates initiation of transcription. We have observed in the rainbow trout protamine gene 3' to the TATA box, three "GC" boxes spaced at 80 bp intervals. The first is 5' to the cap site and possesses the ability to "silence" transcription from the protamine promoter in constructs linking this promoter to the bacterial chloramphenicol acetyl transferase (CAT) coding sequence following transfection to COS-1 cells. A model is proposed to account for the silencing of the protamine gene in all tissues except developing sperm cells.

In vitro expression of two proteins from overlapping reading frames in a eukaryotic DNA sequence

The in vitro expression of two distinct proteins from overlapping reading frames in a sequence of rainbow trout genomic DNA has been demonstrated. In vitro transcription of DNA sequences, cloned in a plasmid under the control of Salmonella phage 6 polymerase promoter, led to the synthesis of two distinct and functional mRNAs corresponding to the protamine mRNA and also to another overlapping mRNA, termed Y. These mRNAs were translated in an mRNA-dependent rabbit reticulocyte lysate cell free system which synthesized the corresponding protein products. Similarities between the synthesized Pro-rich protein Y and three proline-rich proteins, the human salivary Pro-rich protein, the avian sarcoma virus protein P19 and the myc oncogene product, were evident and the significance of these findings is discussed. A synthetic oligonucleotide which is complementary to a sequence corresponding to a region of the Y protein mRNA, but upstream (5') of the transcribed protamine mRNA, hybridized faintly and only to trout brain RNA. However, more sensitive primer extension studies utilizing the Y-specific oligonucleotide detected several Y-related mRNAs in trout brain.

Evidence of sequences resembling avian retrovirus long terminal repeats flanking the trout protamine gene

Additional TATA boxes are present in the flanking regions of trout protamine genes. Their activity as promoters was assayed using an in vitro transcription system. These additional TATA boxes, together with polyadenylation signals that include the consensus AATAAA and CACTG sequences very close to the promoters, suggest that these sequences may be closely related to retroviral long terminal repeat (LTR) sequences. Other features of retroviral LTRs that are also present are short inverted repeats. The LTR-like sequences flanking the trout protamine gene show significant homology to the avian sarcoma virus LTR over a 40-bp region. The trout protamine gene falls into the relatively rare intronless class of eukaryotic genes. This suggests that the gene could have been derived from a processed gene introduced into the genome by reverse transcription of a mature mRNA. The protamine-mRNA-coding region is flanked by AACA... TGTT sequences, which might represent vestigial traces of past recombination events and whose presence supports the notion that the protamine gene sequence was of foreign origin. Recent attempts in this laboratory to transfer the protamine gene into mouse cells have resulted in a high frequency of deletions similar to those observed with constructs in which a retrovirus was used as a vector to transfect foreign DNA with promoters. The distribution of protamine genes in the animal kingdom is very sporadic, which suggests that protamine genes appeared relatively late in evolution. The nonuniform occurrence of the gene among lower vertebrates may have been the result of its horizontal transmission only to certain species, possibly by infection with retroviruses that acquired it from a different species.

Functional prokaryotic gene control signals within a eukaryotic rainbow trout protamine promoter

Following the construction of a series of pSV2-cat derived plasmids containing the chloramphenicol acetyltransferase (CAT) gene under the control of a eukaryotic trout protamine promoter, it was noted that Escherichia coli, transformed with these plasmids, developed resistance to chloramphenicol (CM). This result suggested that the eukaryotic trout protamine promoter possessed significant prokaryotic promoter activity. Modification of the trout protamine promoter region by removing the region containing the eukaryotic Goldberg-Hogness box in the plasmid p525-cat increased the expression of the CAT gene almost to the wild-type level and conferred strong CM resistance. Sequence comparisons of the plasmid series indicate that prokaryotic promoter elements are present in the trout protamine promoter and that their similarity to the prokaryotic promoter consensus sequences and the distance between the two elements is more favourable in p525-cat, the plasmid which confers the greatest CM resistance.

The in vitro transcription of a rainbow trout (Salmo gairdnerii) protamine gene. II. Controlled mutation of the cap site region

A series of plasmids containing new fusion genes in which the trout protamine gene is placed under the control of the complete herpes virus (HSV-1) tk promoter Pvu II-Bgl II fragment (pM8), or a shortened thymidine kinase (tk) promoter in which the region between the TATA box and the cap site is altered by using the Pvu II-Mlu I fragment (pM7), have been constructed. An additional recombinant plasmid was constructed in which the Bgl II-Ava II fragment of the protamine gene containing the entire protamine promoter but missing the protamine coding region was cloned into pBR322 between the Xho II 1666 and Hind III sites (pP5). For in vitro transcription, a HeLa cell lysate system was prepared and the RNA transcription products, after glyoxalation, were electrophoretically analyzed on 5% polyacrylamide gels. In constructing pM8 the DNA sequence between the tk promoter and the cap site was present while in pM7 it was deleted. Similar multiple transcripts were seen in both cases, indicating that the region between the promoter and the cap site has no effect upon transcription in vitro. The multiple transcripts appear to be due to the presence of a cryptic promoter in the complementary strand of the protamine gene. The activity of this cryptic promoter has been confirmed by comparison of the transcription of plasmid pP5, in which the protamine mRNA coding region has been deleted, with a previously described plasmid, pJBRP (Jankowski JM and Dixon GH (1984) Can. J. Biochem. Cell. Biol. 62, 291-300), containing the intact protamine gene.

Transcription of a trout protamine gene in vitro: the effects of alteration of promoters

An in vitro approach has been used to study trout protamine gene expression using various recombinant plasmids containing trout protamine genes as templates in the HeLa cell lysate transcription system. The specific RNA transcript which is protected against S1 nuclease digestion by hybridization to the protamine gene sequence is alpha-amanitin sensitive (1 micrograms/mL), showing that RNA polymerase II is involved. The sizes of transcripts from templates linearized with Bam HI, Rsa I, and Hpa II (all downstream from the putative TATA box) are consistent with those predicted from the known sequence of the protamine gene. Digestion at an Alu I site only 14 base pairs (bp) upstream from TATA box has no effect on the accuracy of transcription in vitro; however, cutting at an Ava II site 9 bp downstream from the TATA box (reading from the first T) abolishes transcription. Chimeric plasmids, in which a herpes simplex virus (HSV-1) thymidine kinase (tk) promoter is tandemly inserted upstream from the trout protamine DNA sequences or as a replacement of the natural protamine promoter, were constructed. Use of these plasmids allowed an examination in a single assay of eight different putative promoter sequences (TATAAAA, TATAAA, TACAAA, TATATA, TATTTAA, CATATTA, TATATTAT, and TATTTAT) that are localized in either the protamine or the tk genes. The canonical TATAAAA promoter (the natural protamine promoter) was the strongest one and, in its presence, none of the others were used significantly for transcription. However, when this promoter was removed the weaker promoters were able to promote transcription.

[Four cases of benign hepatic tumors associated with oral contraception (author's transl)]

The authors have observed 4 cases of benign liver tumors associated with oral contraception. These lesions have been revealed by pains or abdominal tumors, and have been treated by surgery, or not treated. The relations between tumors livers and pill are studied. These tumors are probably frequent and can give acute complications such hemorrhage and perhaps cancer.

[Recto-sigmoid carcinoma after uretero-sigmoidostomy. One case, with a review of the literature (author's transl)]

A case of recto-sigmoid adenocarcinoma, developing 25 years after bilateral uretero-sigmo dostomy for extrophia vesicae in a 29 year old man. A study of the literature emphasises the long delay before its appearance, the gastrointestinal nature of the tumour and its grave prognosis. The pathogenesis of this lesion is unknown at present, and consideration should be given to the effects of urine on the digestive mucosa and the role of a possible inflammatory granuloma, but also the possibility of a urinary tract origin, despite the apparent histological contradiction.